Radio frequency digital to analog converters (RF DACs), digital power amplifier (DPAs), and digital drive amplifiers (DDAs) become more and more attractive for a wireless transceiver design with advance CMOS technology, because of the scalability with the device size shrinking, the easy design for the band width controls, smaller layout area to reduce the die cost, and numerous digital advantages. The so-called all digital transmitter uses a digital block to drive the RF DAC, DPA, or DDA. The digital block, which can be realized as a high-speed digital signal processor (HS DSP), may implement signal up-conversion and data coding. Enhanced designs for HS DSPs are highly desired.